1. Technical Field
Various embodiments generally relate to a smart self-repair device and method, and more particularly, to a technology for improving repair efficiency in a package repair operation.
2. Related Art
A DRAM (dynamic random access memory) is constructed by a plurality of memory cells which are arranged in the form of a matrix. If a fail occurs even in one memory cell among a plurality of memory cells, a semiconductor memory device is sorted as a bad product since it cannot perform properly an operation. According to high integration and high speed operation of a semiconductor memory device, the probability of a failed cell to occur increases.
In a conventional package self repair mode, a repair operation is performed by using only a row redundancy, and a column redundancy is not used. Therefore, in the case where a column-oriented fail occurs, it is impossible to repair the fail, and a package yield cannot help but decrease.
Moreover, in order for saturation of package yield, wafer test conditions should be diversified, and a package yield checking process should be repeated a multitude of times. In such a situation, a yield ramp-up time lengthens, and a number of experiment equipments are needed.